Automatic determining device for phonographs



(No Model.) t T. "A. EDISON.

AUTOMATIC DETERMINING DEVICE FOR PHONOGRAPHS. No. 426,527. Patented Apr.29, 1890 mvarwtoz m a 'mQ UNITED STATES PATENT GEE-ICE.

THOMAS A. EDISON, OF LLEl/VELLYN PARK, NEW JERSEY I AUTOMATICDETERMINING DEVICE FOR PHO NOGRAPHS.

SPECIFICATION forming part of Letters Patent No. 426,527, dated April29, 1890.

Application filed July 2, 1889- Serial No. 316,323. (No model.)

To aZZ whom it may concern:

Be it known that I, THOMAS A. EDISON, a citizen of the United States,residing at Llewellyn Park, in the county of Essex and State of NewJersey, have invented a new and useful Improvement in AutomaticDetermining Devices for Phonographs, (Case No. 835,) of which thefollowing is a specification.

As is-well understood, my phonograph is provided with a device by whichthe relation of the recorder or reproducer with the surface of thephonogram-blank can be accurately determined and the presser-foot thenlooked, so that as it moves along on the guiderest the correct positionof the recorder or reproducer with reference to the surface ismaintained.

My present invention relates to devices of this character and employs apivoted determining-point which is rocked or canted by the rotation ofthe phonogra'm-blank, so as not to impair the surface. Such adetermining-point is described and broadly claimed in .my application,(Case No. 828,) Serial No.

299,460, filed February 11, 1889.

My improvement in respect to this part of the device consists in asimplification of the rocking determining-point and the providing of itwith better means of adjustment, as will presently appear.

A further feature of improvement is the means for locking thepresser-foot by a cammovement, which is readily thrown into and out ofaction and gives a, positive lock entirely independent of thefinger-pieces for raising and lowering the spectacle-frame.

In the accompanying drawings, forming a part hereof, Figure 1 is an endView of sufficient of the phonograph to illustrate the invention, theadjustable head to the rocking determining-point being in section. Fig.2 is a top view of the spectacle-frame detached. Fig. 3 is a bottom viewof a portion of spectacle-frame, showing the adjustable limitingplate;and Fig. 4: is an enlarged view of the determining-point.

A is the revolving phonogram-surface.

B is the rocking holding-arm, carrying the swinging spectacle-frame (J.

D is the guide-rest, and E E are the presserfoot bars, which passthrough the fingers a of the spectacle-frame, such fingers terminatingin knobs b for raising and lowering and swinging the frame.

Instead of mounting the rocking determining-point upon abar pivoted tothe spectacleframe, as described in the application before referred to,each determiningpoint is composed of a bolt F, which is pivoted directlyin the spectacle-frame, the bolt having an eye in its upper end,entering a slot in the spectacle-frame from the under side of the frameand pivoted therein by a cr0ss-pin. One of these bolts is provided foreach eye of the spectacle-frame, so as to provide the means foradjusting both the recorder and reproducer with reference to thephonogramsurface. The end of the bolt F is screwthreaded, and upon itturns a head G, which has a rounded polished surface (formed on a curveof which the pivot of the bolt is the center) and is secured fromturning on the bolt by means of a set-screw o. By turning the head Gupon the bolt F the bolt is shortened or lengthened, and a fineadjustment is thus secured, which is maintained by setting the screw 0.The bolt F passes through a slot (l in a plate H, secured to the underside of j I the spectacle-frame by means of a slot 6 and a screw f, sothat said plate Hcan be adjusted. The slot d in the plate H limits theswinging movement of the determining-point. Since the. swinging bolt Fis oblique to a vertical line, it will swing by its own weight againstthe lower side of the slot cl in the plate H, and it is in this positionthat the head G strikes the surface of the phonogram-blank anddetermines the adjustment.

The presser-foot bars E E are made of a cam shape, and upon the top ofthe fingers a are provided plates 9, which have a similar cam-shapedopening, through which the presser-foot bars pass. This cam is of aspiral shape, so that a slight turning movement of the presser-foot barswill lock them in the plate g. A pin h projects from the top of eachpresser-foot bar, by which it isturned to lock or unlock it in the plateWhen unlocked, the presser-foot bars fall through the fingers a of thespectacle-frame by gravitation or by means of springs, as in the formerdevices employed by me.

. The operation of performing the adjustment is as follows: The rotatingmovement of the phonogram-surface is arrested and the spectacle-frame islowered, the presser-foot bar being free in the finger of the frame andprojecting downwardly to its lowermost limit. The presser-foot firststrikes the guide-rest D, and as the downward movement of the framecontinues the finger of the spectacleframe slides down over thepresser-foot bar. The head G strikes the surface of the phonogram-blank,arresting the further downward movement of the spectacle-frame anddetermining its point of adjustment with relation to the surface. Thepin h is then drawn slightly toward the operator and locks thepresser-foot bar positively in the finger of the spectacle-frame. Now,when the phonogram-blank begins to rotate in the direction shown by thelarge arrow in Fig. 1 the determining-point, being pivoted, will rockslightly upon its pivot and relieve the sur face of injurious pressure.

The simple cam-locking device operated by a partial rotation of thepresser-foot bar is an exceedingly effective lock, and might be usedwith other forms of determining-point. If the bar is locked by aturningscrew which forms the end of the finger of the spectacleframe, as in theapplication referred to, there is a tendency to move the spectacle framein turning the locking-screw, usually by exerting an additional downwardpressure upon it. The proper adjustment being such that the turning-offtool of the phonograph will enter the phongram-surface only to theextent of two one-thousandths of an inch, it will be seen that even aslight pressure may result in forcing the determining-point into thesurface far enough to destroy the accuracy of the adjustment. Thecam-lock being alocking device whose movement by the fingers of theoperator is independent of the movement of the spectacle-frame in thesense that it does not tend to disturb the position of thespectacle-frame or exert strain upon it, an entirely accurate adjustmentcan be readily secured without the exercise of extreme care.

Any suitable arrangement of a locking-cam operated by a separatefinger-piece can be used. Many such differing in detail from that shownand described would occur to the skilled mechanic.

What I claim as my invention is- 1. In a phonograph, the combination,with the spectacle-frame, of the determining-point pivoted directly uponsuch frame, substantially as set forth.

2. In a phonograph, the combination, with the spectacle-frame, of apivoted determining-point pivoted directly upon said frame and having anadjustable head, substantially as set forth.

3. In a phonograph, the combination, with the spectacle-frame, of apivoted determining-point and an adjustable limiting-plate for limitingthe swinging movement of the point, substantially as set forth.

4:. In a phonograph, the combination, with the spectacle-framepresser-foot bar, and guide-rest, of a lock the movable element of whichis carried by the presser-foot bar, operated independently of andwithout exerting any strain upon the spectacle-frame for fixing theposition of said spectacle-frame on the presser-foot bar, substantiallyas set forth.

5. In a phonograph, the combination, with the spectacle-frame,presser-foot bar, and guide-rest, of a cam-lock the movable element ofwhich is carried by the presser-foot bar, operated independently of andwithout exerting any strain upon the spectacle-frame for fixing theposition of said spectacle-frame on the presser-foot bar, substantiallyas set forth.

6.. In a phonograplnthe combination, with the spectacle-frame, of acam-shaped presserfoot bar passing through a camshaped opening in thefinger of the spectacle-frame and locked therein by partial rotation,substantially as set forth.

'7. In a phonograph, the combination, with the spectacle-frame,presser-foot bar, and guard-rest, of a determining-point pivoteddirectly upon the spectacle-frame and a lock the movable element ofwhich is carried by the presser-foot, operated independently of andwithout exerting any strain upon the spectacle-frame for fixing theposition of said spectacle-frame on the presser-foot bar with relationto the position of the determiningpoint, substantially as set forth.

This specification signed and witnessed this 15th day of June, 1889.

v THOS. A. EDISON. WVitnesses:

WILLIAM PELZER, RIoHD. N. DYER.

